I personally still hold that having “High Elves” in any fashion was a mistake, and undermine the entire story-arc they had during Warcraft III (which was further instilled in the BE starting area), but at least High Elves are compatible with all classes. Having additional “Void customizations” would be more appropriate, since the canon would obviously be that you’re still a High Elf.
While I dig having new options, I just think these were poorly thought out.
Don’t get me wrong: I want to play a Broken. (I’d have taken Broken over the damn man’ari eredar options—aside from the new hair and eye colors, that is—any day. And I wish making two of my draenei into Lightforged had been a matter of hitting the barber shop rather than choosing between race-changing and rerolling. But the claim that Lightforged wouldn’t be able to use other forms of magic is erroneous; there’s been at least one archmage among their number since their introduction (as in: before they were even playable).
It’s not that they’re incompatible with any form of magic. But that they are very explicitly incompatible with Fel and Void magics.
And unlike most races, which are biologically unique races, the Lightforged only became Lightforged by undergoing a very specific ritual choosing to infuse their bodies with the Light. I’ll be honest, the justification doesn’t really make a whole lot of sense for any other class besides Paladin or Priest, but at least it doesn’t directly contradict lore. But it does with Warlock.